Vegetative propagation through cell or tissue culture is known as macropropagation.

Explanation:
Vegetative propagation is a method of plant reproduction that does not involve the formation of seeds or spores. Instead, it allows plants to reproduce asexually by producing new individuals from vegetative parts such as stems, leaves, or roots.

One method of vegetative propagation is through cell or tissue culture, which involves the growth and development of plant cells or tissues in a controlled laboratory environment. This technique allows for the production of multiple identical plantlets from a single parent plant, a process known as macropropagation.

Advantages of Macropropagation:
1. Genetic uniformity: Since macropropagation produces multiple identical plantlets from a single parent plant, it ensures genetic uniformity among the propagated plants. This can be advantageous in situations where the desired traits of the parent plant need to be maintained in the offspring.

2. Rapid multiplication: Macropropagation allows for the rapid production of a large number of plantlets within a relatively short period of time. This can be beneficial for commercial plant production or for the conservation of endangered plant species.

3. Disease-free propagation: By using sterile laboratory conditions and carefully selected plant tissues, macropropagation can help eliminate pathogens or diseases that may be present in the parent plant. This ensures that the propagated plants are free from infections and diseases, leading to healthier and more vigorous offspring.

4. Propagation of difficult-to-root plants: Some plant species or varieties may have a low rooting capacity, making traditional methods of vegetative propagation challenging. Macropropagation, through tissue culture, provides a means to overcome these difficulties and successfully propagate such plants.

5. Year-round propagation: Macropropagation can be carried out throughout the year, regardless of the plant's natural propagation season. This allows for continuous plant production and the ability to produce plants out of season.

In conclusion, macropropagation through cell or tissue culture is a valuable technique for vegetative propagation. It offers several advantages, including genetic uniformity, rapid multiplication, disease-free propagation, propagation of difficult-to-root plants, and year-round propagation. This technique has significant applications in plant breeding, commercial plant production, and the conservation of plant species.